Well, there's no scripture that says a husband can 'force' a wife to do anything, sexual or not. I know the law in the US is that forcing your spouse into sexual acts is still technically rape.
Men are not to take a woman by force in any manner, rather she is to submit to him, and he is to be honoring and respectful of her in her submission as to not take advantage of her but 'love her as Christ loves the church'. Which means he cannot force his will on a woman, just like Christ would not force his will on one of us. So while this answer may not be directly about anal sex, it is about any use of force of a husband on a wife.
Husbands, love your wives, just as Christ loved the church and gave himself up for her to make her holy, cleansing her by the washing with water through the word, and to present her to Himself as a radiant church, without stain or wrinkle or any blemish, but holy and blameless. In this same way, husbands ought to love their wives as their own bodies. He who loves his wife loves himself. After all, no one hated his own body, but he feeds and cares for it, just as Christ does the church — for we are members of His body. For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh. This is a profound mystery-but I am talking about christ and the church. However, each one of you also must love his wife as he loves himself, and the wife must respect her husband. Ephesians 5:25-33